OCZ 400W PSU (+12V @ 31A) for $39.99 after rebate and free shipping

I live in England and i was wondering if it would better for me to purchase these item in dollars or in pounds? (I know that some items are cheaper in other countries) so If I paid in dollar and lose some money is exchange rates would it still be cheaper than buying them in pounds?
sorry if this is in the wrong place :S